Method of storing and transporting gases



1,680,873 P. N. LUCAS-GIRARDVILLE IETHOD OI STORING AND TRANSPORTING QASIS Filed lay 18, 1926 IIIIII III! 7 T 1 Patented Aug. 14, 1928. v UNITED. STATES PATENT OFFICE.

ram. moons LUCAB-GIRARDVILLE, or rams, rmcn.

METHOD OF STORING AND TBANSPORTING GASB;

Application filed Kay 18 1926, serial No. 110,021, and in France 19420, 181

This invention relates to a method of storing and transporting gases in the liquefied or solid state. V

Liquefaction of gases is obtained, as is known, either by com ression, or by cold, or by a combination 0 these two means.

Choice between the several processes is not.

however generally free. In the case of the so-called permanent gases, in fact the liquid .state, can only be obtained by brin 'ng the gas to a very low temperature and eeping it there. In order to realize these conditions it is indispensable that the containers used be so arranged as to allow heat to pass only very slowly. It is then possible in containers thus arranged to maintain the gas liquid at atmospheric pressureduring along time for intended practical applications, provided that the calories which pass through the easing are absorbed by the latent heat of evaplow. Consequently one is led to enclose the 7 container in a casing as athermanous as possible.

vThe invention relates to casingscapable of fulfilling these conditions. The ordinary heat insulators being as is well known insufiicient to solve the problem in question, recourse is had to devices based on the principle of the Dewar double-walked flask, which as already been employed, after the first applications to liquid air, oxygen and nitrogen. However the transport of large uan- .tities of liquefied gas would lead, i. the .usual constructions were employed, to Dewar flasks of prohibitive dimensions, the difficulties and the costs. of construction of which would constitute an insurmountable barrier. I

According to the invention containers are used of suitable material, sheet iron for exam 1e, which are covered by a platin of m tiple contiguous members, each of w ich has the characteristics of the Dewar flask (very high outer vacuum, highly olished surfaces, either silver orcopper p ated so as to possess a ver high reflecting power).

The contiguity 0 these Dewar mem rs, with the covering, if necessary, of the joints with members constituting a second protective layer, protects the inner container against heat almost as well as if it were made v in one piece in accordance with the principles cons dered.

It is moreover to be noted that, tor the transport of non-permanent gases, which can be liquefied by pressure alone and consequent y remain liquid at the surrounding temperature, it is not the same thing whether the containers for tansport be made with athermanous casings of the type above de-- scribed or with ordinary casings.

It is in fact known that the vapour tension of gases thus liquefied increases very quickly with the "temperature. One is thus led, even when they are provided with safety devices to prevent the pressure from increasing in an exaggerated way, to provide a resistance considerably greater than that which would suit the normal temperature of use. A considerable part of the gain in weight is thus lost (economy infirst cost and in cost of frei ht).

I on the contrary these containers are made with athermanous walls, they may beconstructed of much less weight, as 1t is known that the inside temperature, and consequently the pressure, will not vary much,

even during a fairly long transport.

It will be observed finally that this system, combining light construction with the use of athermanous walls is equally applicable forv the transport of permanent gases liquefied by the .use of cold, if it be desired, to avoid loss by evaporation. If in fact protection against heat be efiiciently obtained, the quantity of calories which enters the gaseous mass is fairl small, the rise intemperatureof the fluid during the time of trans ort will not exceed a temperature sufliclently distant from the critlcal point,

forthe transport to be carried out in conditions of suita 1e security, rovided of course that there is a suitable sa ety device for the case in which the pressure would become higher than the value corresponding to the resistance of the casing.

The employment of athermanous walls is also of a kind to afford particularly inter-' esting advanta es in special cases where two ases having lfferent properties and boiling temperatures are to be transported.

The container for transport must naturally be made in a special wa For example it may be made in the 0 lowing way as shown diagrammatically in the accompanying drawing.

An inner casing 1, not athermanous, contains one of the gases to be transported for example methane, either liquefied or SOhd.

A second athermanous casing 2 surrounds the former at a certain distance in such way that there is circulating space 3 between the two walls. The bottom of the casing 2 is rovided preferably with a cavity 4 which holds a reserve of liquid nitrogen. At the upper part is an opening 5 for the escape o the nitrogen vapour.

If a certain quantity of liquid nitrogen for example boiling at minus 195 be stored in the lower part of the container between the two casings the nitrogen vapour eir-' culating between the two casings will maintain the inner body of methane at the like temperature. Now, methane solidifies at about minus 184. It will thus be kept in the solid state so long as the nitrogen has not entirely evaporated. It will thus be ossible to transport this as or other similar gases solidified by col in the same conditions of duration as if liquid nitrogen, oxy en or air were being transported.

These conditions of transport are particularly interesting in its app ication to aeronautics for example. In fact it is possible by means of suitable apparatus to liquefy and then to vaporize the methane carried by the aeroplane in containers of the kind hereinbefore described to suit the needs of the engine. These operations are carried out very easily owing to the ver great difference of temperature existing between the body to be volatilized and the elements (air or exhaust gas) employed for the reheating.

The quantity of methane thus volatilized to supply the engine being at each instant extremely small in comparison with the total quantity of fuel carried on board, the risks of fire resulting from a leak are themselves much reduced. They are the more so because the body remaining in the liquid state only during a very short time, the" quantity of methane in question is vaporized and diffused instantaneously into the atmosphere, whilst a liquid such as benzene or petrol spreads into the cock-pit or gives off heavy vapours very dangerous from the point of view of fire-risk.

Even if, in the event of a bad landing, the containeris burst, the methane being in the solid state does not instantaneously become liquid, which alone allows of a dangerous diffusion, and the firing of the engine is consequently out off before a fire can have starte Furthermore if the container constructed as described on a fighting plane is pierced by a bullet, the methane being solid and continuing to remain so owing to the circulation of the nitrogen, there 1s no leak of fuel. Moreover even if it be an incendiary bomb since it passes through a layer of nitrogen before penetrating into the methane or re-entering the atmosphere after penetration, it cannot set fire to the fuel.

This protection from fire remains moreover very eflicacious in the case of transport by tank wa ons, especially in warfare. It

is extended or such transport to highly inflammable liquid fuels such a petrol, alcohol and ether, for example, although these fuels have very low melting points (minus 98 for toluene, minus 130 for alcohol, minus 118 for ether) they can be violently frozen and kept in that state by the processes above described, so as to do away with fire risks in transport and storage both in times of peace as well as in times of warfare.

These double-Walled containers may moreover be em loyed by means of an accessory device for t e transport of ases which have not been brought into the liquefied state.

It is known that certain sohd bodies, wood charcoal amongst others, have the pro erty of absorbin a lar e volume of gas. heir ability to absorb epends both on the storage pressure and on the temperature of the charcoal at the moment of absorption. The temperature in particular has a very great influence on the proportion of gas absorbed; thus at the temperature of liquid air one volume of charcoal absorbs 135 volumes of hydro en at atmospheric pressure.

If t en the inner space of the doublewalled containers above described is pro vided with a charcoal lining, the annular space being itself partly filled with liquid nitrogen, these containers will allow of the transport of hydrogen for example, under conditions as to weight, much more economical than those of the present systems of transport.

To sum up, this a plication of doublewalled containers wit an outer athermanous casing and circulation of liquefied gases between the two walls comprises the same improvements with the same advantages as the transport of gases liquefied or solidfied by cold. Thus the principle'of the double wall with circulation of nitrogen allows either of transporting a very great volume of hydrogen under a pressure of a few kilogrammes, or even of transporting a volume of it comparable with that which is contained in the usual cylinders, but working at a pressure slightly below that of the atmosphere, and therefore without risk of leakage or of fire.

The arran ements described can also be used for or mary cold trans ort. In this case the athermanous casing elays heating during a very long time, the difierence between the outside temperature and that of the frozen provisions being much less great than in the case of liquid air and the passage o tfJ calories being consequently less considera le.

Moreover the plant can be completed by the arrangements described, to allow of keeping a cold storage wagon thus constructed for several days within the limits of temperature rendered necessary by the nature of the goods transported.

The same arrangements may beapplied in the case of rooms or reservoirs in whic I there is maintained a temperature sufiicient- 1y low by a-circulation of brine or other cooling liquid. The use of the proposed systemcby considerably reducing the transmission of heat allows of the reduction to a considerable extent of the expenditure of motivepower required operating the refrig erating plant in question.

Claim The method of storing a substance whose boiling point is below 0 Cr, in a condensed state such as a liquid or solid which com- .pri'ses enclosing said substance in a heat conducting vessel which is in heat conductmg contact with a liquid exposed to atmosinsulated vessel, said liquid having a lower boiling point than the said substance whereby the slow and gradual evaporation of the liquid acts to maintain the said substance in its condensed state.

In testimony whereof I aifix my signature.

PAUL NICOLAS LUCAS-GRANVILLE.

pheric pressure and maintained in a heat I 

